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authorLu Baolu <baolu.lu@linux.intel.com>2018-03-08 18:17:15 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-08 20:06:53 +0300
commita098dc8b03d1c7284ed98d921224fffa15b13ece (patch)
tree4bfd0bd7ff912a89b5f3367b599aa1e3130aaccf /drivers/usb/host/xhci-dbgtty.c
parent97ef0faf575e03b352553f92c9430cb4c0431436 (diff)
downloadlinux-a098dc8b03d1c7284ed98d921224fffa15b13ece.tar.xz
usb: xhci: dbc: Fix lockdep warning
The xHCI DbC implementation might enter a deadlock situation because there is no sufficient protection against the shared data between process and softirq contexts. This can lead to the following lockdep warnings. This patch changes to use spin_{,un}lock_irq{save,restore} to avoid potential deadlock. [ 528.248084] ================================ [ 528.252914] WARNING: inconsistent lock state [ 528.257756] 4.15.0-rc1+ #1630 Not tainted [ 528.262305] -------------------------------- [ 528.267145] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. [ 528.273953] ksoftirqd/1/17 [HC0[0]:SC1[1]:HE0:SE0] takes: [ 528.280075] (&(&port->port_lock)->rlock){+.?.}, at: [<ffffffff815396a8>] dbc_rx_push+0x38/0x1c0 [ 528.290043] {SOFTIRQ-ON-W} state was registered at: [ 528.295570] _raw_spin_lock+0x2f/0x40 [ 528.299818] dbc_write_complete+0x27/0xa0 [ 528.304458] xhci_dbc_giveback+0xd1/0x200 [ 528.309098] xhci_dbc_flush_endpoint_requests+0x50/0x70 [ 528.315116] xhci_dbc_handle_events+0x696/0x7b0 [ 528.320349] process_one_work+0x1ee/0x6e0 [ 528.324988] worker_thread+0x4a/0x430 [ 528.329236] kthread+0x13e/0x170 [ 528.332992] ret_from_fork+0x24/0x30 [ 528.337141] irq event stamp: 2861 [ 528.340897] hardirqs last enabled at (2860): [<ffffffff810674ea>] tasklet_action+0x6a/0x250 [ 528.350460] hardirqs last disabled at (2861): [<ffffffff817dc1ef>] _raw_spin_lock_irq+0xf/0x40 [ 528.360219] softirqs last enabled at (2852): [<ffffffff817e0e8c>] __do_softirq+0x3dc/0x4f9 [ 528.369683] softirqs last disabled at (2857): [<ffffffff8106805b>] run_ksoftirqd+0x1b/0x60 [ 528.379048] [ 528.379048] other info that might help us debug this: [ 528.386443] Possible unsafe locking scenario: [ 528.386443] [ 528.393150] CPU0 [ 528.395917] ---- [ 528.398687] lock(&(&port->port_lock)->rlock); [ 528.403821] <Interrupt> [ 528.406786] lock(&(&port->port_lock)->rlock); [ 528.412116] [ 528.412116] *** DEADLOCK *** [ 528.412116] [ 528.418825] no locks held by ksoftirqd/1/17. [ 528.423662] [ 528.423662] stack backtrace: [ 528.428598] CPU: 1 PID: 17 Comm: ksoftirqd/1 Not tainted 4.15.0-rc1+ #1630 [ 528.436387] Call Trace: [ 528.439158] dump_stack+0x5e/0x8e [ 528.442914] print_usage_bug+0x1fc/0x220 [ 528.447357] mark_lock+0x4db/0x5a0 [ 528.451210] __lock_acquire+0x726/0x1130 [ 528.455655] ? __lock_acquire+0x557/0x1130 [ 528.460296] lock_acquire+0xa2/0x200 [ 528.464347] ? dbc_rx_push+0x38/0x1c0 [ 528.468496] _raw_spin_lock_irq+0x35/0x40 [ 528.473038] ? dbc_rx_push+0x38/0x1c0 [ 528.477186] dbc_rx_push+0x38/0x1c0 [ 528.481139] tasklet_action+0x1d2/0x250 [ 528.485483] __do_softirq+0x1dc/0x4f9 [ 528.489630] run_ksoftirqd+0x1b/0x60 [ 528.493682] smpboot_thread_fn+0x179/0x270 [ 528.498324] kthread+0x13e/0x170 [ 528.501981] ? sort_range+0x20/0x20 [ 528.505933] ? kthread_delayed_work_timer_fn+0x80/0x80 [ 528.511755] ret_from_fork+0x24/0x30 Fixes: dfba2174dc42 ("usb: xhci: Add DbC support in xHCI driver") Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci-dbgtty.c')
-rw-r--r--drivers/usb/host/xhci-dbgtty.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/drivers/usb/host/xhci-dbgtty.c b/drivers/usb/host/xhci-dbgtty.c
index 8d47b6fbf973..75f0b92694ba 100644
--- a/drivers/usb/host/xhci-dbgtty.c
+++ b/drivers/usb/host/xhci-dbgtty.c
@@ -92,21 +92,23 @@ static void dbc_start_rx(struct dbc_port *port)
static void
dbc_read_complete(struct xhci_hcd *xhci, struct dbc_request *req)
{
+ unsigned long flags;
struct xhci_dbc *dbc = xhci->dbc;
struct dbc_port *port = &dbc->port;
- spin_lock(&port->port_lock);
+ spin_lock_irqsave(&port->port_lock, flags);
list_add_tail(&req->list_pool, &port->read_queue);
tasklet_schedule(&port->push);
- spin_unlock(&port->port_lock);
+ spin_unlock_irqrestore(&port->port_lock, flags);
}
static void dbc_write_complete(struct xhci_hcd *xhci, struct dbc_request *req)
{
+ unsigned long flags;
struct xhci_dbc *dbc = xhci->dbc;
struct dbc_port *port = &dbc->port;
- spin_lock(&port->port_lock);
+ spin_lock_irqsave(&port->port_lock, flags);
list_add(&req->list_pool, &port->write_pool);
switch (req->status) {
case 0:
@@ -119,7 +121,7 @@ static void dbc_write_complete(struct xhci_hcd *xhci, struct dbc_request *req)
req->status);
break;
}
- spin_unlock(&port->port_lock);
+ spin_unlock_irqrestore(&port->port_lock, flags);
}
static void xhci_dbc_free_req(struct dbc_ep *dep, struct dbc_request *req)
@@ -327,12 +329,13 @@ static void dbc_rx_push(unsigned long _port)
{
struct dbc_request *req;
struct tty_struct *tty;
+ unsigned long flags;
bool do_push = false;
bool disconnect = false;
struct dbc_port *port = (void *)_port;
struct list_head *queue = &port->read_queue;
- spin_lock_irq(&port->port_lock);
+ spin_lock_irqsave(&port->port_lock, flags);
tty = port->port.tty;
while (!list_empty(queue)) {
req = list_first_entry(queue, struct dbc_request, list_pool);
@@ -392,16 +395,17 @@ static void dbc_rx_push(unsigned long _port)
if (!disconnect)
dbc_start_rx(port);
- spin_unlock_irq(&port->port_lock);
+ spin_unlock_irqrestore(&port->port_lock, flags);
}
static int dbc_port_activate(struct tty_port *_port, struct tty_struct *tty)
{
+ unsigned long flags;
struct dbc_port *port = container_of(_port, struct dbc_port, port);
- spin_lock_irq(&port->port_lock);
+ spin_lock_irqsave(&port->port_lock, flags);
dbc_start_rx(port);
- spin_unlock_irq(&port->port_lock);
+ spin_unlock_irqrestore(&port->port_lock, flags);
return 0;
}